I have written tons of fabfiles and Fabric is a great project. However it isn't intended to managed system state. It is great for code deployment but not suited to configuration management.
Fabric does what we need it to do for now for provisioning & deployment. And frankly you can make it do whatever you want. "Programmatic use of SSH" isn't something to be scoffed at; it's simple yes but it also lets you do whatever the hell you want very simply.
My current workflow for managing systems does use Fabric however. I maintain configuration using a custom framework and work under git/hg -- Fabric tarballs the tip, syncs the tarball to several dozen servers, and then runs and my configuration module on each server. I did use a bash script previously though.
We are in the process of moving away from Capistrano to a system where code is automatically deployed when a new release is tagged. The deployment system is automatically managed with Puppet and everything is monitored with Nagios.